The present invention pertains to a sealant composition. More particularly, the present invention is directed to a sealant composition that is fluid in its uncured state and can be cured by processes such as UV, heat, or combinations of both. Finally the present invention is directed to a sealant for application to the underside flange of a headed fastener for the purpose of sealing as well as to fasteners so configured.
Various types of fastening applications require effective sealing interface between surfaces of the fastener and the associated substrate body. In headed fasteners, many assemblies require fluid tight seals between the head or flange and the corresponding surface. Initially, various independent seal members have been employed for this purpose. The need for speed and accuracy in assembly processes encouraged fasteners with sealant materials that has been integrated on to the associated fastener members prior to assembly. In such configurations, sealant material proximate to the underside or flange of the fastener is compressed between the underside or flange and a second surface to seal against The need for effective sealant formulations and for fastener-sealant combinations as well as effective sealant materials still continues.
In order to accomplish effective sealing, the sealant material employed should have sufficient conformational stability and compressiblilty. Many of the sealant materials employed incorporate curable polymeric materials that required processing under high temperature and/or high pressure for extended intervals in order to attain desired properties.
Ethylene acrylic elastomers (also referred to by their ISO1629 code as AEM Rubber) are currently used in the field for their heat and fluid resistant properties. These AEM materials in the raw form are solid and rubber like which can be extruded or injection molded to predetermined shapes, sizes and configurations and then cured by vulcanization. Formation of these structures requires processing at high temperatures and pressures for substantial lengths of time. Various types of structures for automotive applications such as radiator hoses, gaskets and seals can be made by these materials and processes. By compound blending AEM with its complimenting curing agent and a host of modifiers various properties can be obtained such as hardness, elongation, fluid resistance, and compression set. The AEM materials currently employed are unable to provide sealant properties when processed at lower temperatures and/or pressures and/or with shorter vulcanization times to create elements for gasketing or sealing.
It would be desirable to provide a sealant material for the underside or flange of a headed fastener that is subject to at least partial cure at ambient or lower temperatures as well as a fastener that includes the same. It would also be desirable to provide sealant materials that are flowable prior to curing that will provide a seal material that is resistant to elevated temperatures and various fluids throughout the lifetime of the fastener and associated product.